Nuclear Biosphere

“An Isotope is not just a baseball player”

Nuclear medicine is a branch of medical imaging that uses small amounts of radioactive isotopes to diagnose and determine the severity of or treat a variety of diseases, including many types of cancers, heart disease, gastrointestinal, endocrine, neurological disorders and other abnormalities within the body.

Most of my readers are the older folks in town and many of us have visited the radiology department at our local hospitals at one time or another. Radiologists use a variety of imaging techniques such as X-ray radiography, ultrasound, computed tomography (CT), positron emission tomography (PET) and magnetic resonance imaging (MRI) to diagnose or treat medical conditions. Have you ever wondered exactly how these diagnostic imaging or treatment devices worked or what was in that cocktail they made you drink or injected into your IV?

In last week’s article I tried my best to introduce and define the elements that are used in a nuclear reactor to create ‘heat’ for generating electricity. In the process known as fission, the atoms are split and create (transmute) other elements or isotopes. Some of these isotopes are extremely valuable to medical diagnostics and radiation therapy. What are these isotopes, where do they actually come from, how are they used in medical procedures and what happens to the radioactive materials after the procedures? Hmmm!

Over 10,000 hospitals worldwide use radioisotopes in medicine, and about 90% of the procedures are for diagnosis. The most common radioisotope used in diagnosis is technetium-99m (Tc-99m), an element not easily found in nature, but obtained from the fission of highly enriched uranium (HEU) in a nuclear reactor that creates molybdenum-99 with a half-life of 66 hours. The Mo-99 decays to Tc-99m which is the base substance in the safe cocktail used as a tracer for a CT scan. The take away here is that we need nuclear reactors for our medical specialty products and procedures, which my wife and I have had our share of already.

How safe is it? The Tc-99m radiation dose a person receives is very small and only last 6 hours. Since the detectors to scan your body are quite sensitive, only a tiny amount is needed. Your body naturally rids itself of the Tc-99m within a few days after receiving it. The minimal level from the procedure means your body sees only a small fraction of radiation that you normally receive from other natural background radiation from the ground we walk on and the sky we walk under. Radiation is all around us all the time.

This is where an advanced Liquid Fluoride Thorium Reactor (LFTR) can play a huge role in the future production of many medical isotopes. Beside the production of Mo-99 which decays to Tc-99m for diagnosis, the LFTR can also produce an isotope chain to Bismuth-213 which is currently unobtainable naturally, but has the potential to be used in new types of advanced cancer treatments, such as Targeted Alpha Therapy (TAT) for brain cancer and other very critical cancers.

A LFTR can also produce Strontium-89, Xenon-133, Iodine-131, and Yttrium-90 to name a few of the more than 160 radioisotopes of 80 chemical elements used in diagnosis and therapy. The take away here is that many medical isotopes can be produced and extracted in a single LFTR, while it is also producing extreme heat for electricity generation or water desalination.

What the world needs now is a little love, as well as a few multipurpose LFTRs, which is one of the reactor designs for molten salt heat transfer technology, the energy future and the topic of my next article.